Providing adequate lubrication to the components of an interaxle differential is important to the operation and longevity of the automotive drive axle system. For example, it is important to properly lubricate the various gears and pinions of the axle assembly including their teeth and the bearing surfaces on which they are supported for rotation. Typical lubricating systems for interaxle differentials provide a gear driven pump for positive supply of lubricating oil to various elements within the interaxle differential. However, it is not uncommon to use splash lubrication, although not as reliable as pump lubrication, it is less expensive. In splash lubrication, lubricant clings to the rotating component as it passes through the lubricant in the sump and is thereafter slung outwardly from the rotating component due to centrifugal force. Splash lubrication does not generally insure that lubricating oil will be accurately or sufficiently supplied to the various elements requiring lubrication. Splash lubrication is also disadvantageous because system components that churn the lubricant and cause it to splash are exposed to drag forces. The drag forces reduce efficiency of the system.
It would be desirable for a drive axle system to maintain operating efficiency, while also ensuring all the differential components are adequately lubricated for performance and longevity.